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Martyn's Law capacity calculator. Find your busiest day, then see where you stand.

Martyn's Law counts the most people in your building at the same time, on your busiest occasion. Fill in your busiest occasion and this works out your peak against 200 and 800.

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Your busiest occasion

Count the most people there at once, not everyone who comes and goes over the day. Not sure which day is busiest? Add another to compare.

Or pick one:

    Your answers stay on this page. Nothing is sent or stored.

    Your busiest occasion shows here

    Add a number to any occasion to see your peak.

    How to count in three rules

    The Home Office's test is the greatest number of people reasonably expected there at the same time, from time to time.

    Read the full guide to counting

    1. 1

      At the same time

      How many are there at once, not how many come through the door over the day. Count each busy moment on its own.

    2. 2

      Everyone counts

      Visitors and guests, your staff and volunteers, and performers, caterers and stallholders too.

    3. 3

      Peaks, not averages

      Busy occasions count even once a year. A quiet week doesn't bring your number down.

    Questions about counting

    Who counts towards the 200?

    Everyone there at the same time: visitors and guests, your staff and volunteers, and people like performers, caterers and stallholders. If you're just under 200 guests, the people working can take you over.

    Do I add up everyone who comes in over the day?

    No. Count the most people there at any one moment. Three services on one day, or a morning group and an evening class, are separate busy moments, so don't add them together.

    Our biggest event only happens once a year. Does it count?

    Yes. Busy occasions count even if they come round once a year, like a festival or a summer fair. Averages don't count, so a quiet week doesn't bring the number down.

    Is anything I type sent anywhere?

    No. The sums are done on this page, in your browser. Nothing is sent or stored, and it's all gone when you close the page.

    Got your number? Check your venue.